It is known that a heat receiver which receives heat from a heat-generating part or the like and cools the heat-generating part or the like mounted on a printed circuit board installed in an electronic apparatus. A flow path through which a refrigerant flows is formed within the heat receiver. To improve the heat-receiving efficiency of the heat receiver, it is conceivable to increase a flow velocity of the refrigerant. For example, the flow path is designed so as to reduce a cross sectional area of a part of the flow path corresponding to a high temperature region of the heat-generating part, which increases the flow velocity of the refrigerant in the part, partially improving the heat-receiving efficiency. A technique related to such a heat receiver is disclosed in Japanese Patent Application Publication Nos. 2004-134742, and 2012-28720.
Temperature distribution of the heat-generating part is changed in accordance with elapsed operating time of the heat-generating part or an operating condition thereof. For example, in some cases, the temperature of the whole heat-generating part is low, or the temperature of a part thereof is high. When the temperature of the whole heat-generating part is low, it is preferable that the cross sectional area of the flow path is large to some extent in order to reduce pressure loss. In contrast, when the temperature of a part of the heat-generating part is high, it is preferable that the cross sectional area of a part of the flow path corresponding to a high temperature region of the heat-generating part is small to some extent in order to improve the heat-receiving efficiency of receiving heat from the heat-generating part. However, a conventional heat receiver is not capable of changing the cross sectional area of the flow path on the basis of temporal change in the temperature distribution of the heat-generating part.